Tipsarevic: 'I could not be more pissed off'

Maria Sharapova thrashed Kirsten Flipkens for the loss of only one game and was delighted with how she retained her focus. She said: "It's really about keeping your focus and no matter what the score is, no matter if you're up. I didn't start the match really great. I was facing a different type of opponent today and I was making a few more mistakes than I would have liked in the beginning. But after I held at 2‑1, I really started making her play a little bit more. Started really getting under the ball and being aggressive and just had a little bit more energy, which really helped me and I carried that throughout the match. It's always much easier said than done to keep that focus."

Ekaterina Makarova was impressive in beating Angelique Kerber, ending a lengthy losing run against the German in the process. She said: "Everything is, the crowd is so perfect, my team is [doing a] great job, I'm so happy. I'm so happy to beat Kerber because last year I lost three times to her. I'm so happy."

Angelique Kerber was troubled by a back problem against Makarova and it restricted her on serve. She said: "I could move; that was fine. But just my serve, when I go back, there is a lot of pain there. I've actually feel it like two, three days. So I was thinking it will be maybe not too bad, but in the first set I was feeling that and it was actually worse and worse. Also I take the treatment. But it was not too good."

Janko Tipsarevic retired against Nicolas Almagro with a foot injury and is unsure of the extent of the problem. He said: "I don't know how I managed to do it but I completely screwed up my left heel. I haven't seen the doctor yet... and I don't know what he's going to say.

"Nico (Almagro) was playing great tennis, hitting the ball powerfully from both wings. But I was feeling great today, I wasn't feeling tired at all from my previous matches. It was a beautiful day for tennis and I really felt I could play well. And I could not be more pissed off with the way I finished the competition."

Nicolas Almagro's reward for beating Tipsarevic is a meeting with David Ferrer, a player he has never beaten in 12 previous clashes. He said: "I never beat him, but maybe here will be the first time. It will be a good fight. I know him, he knows me. We never played in a grand slam ... it's a big opportunity for me to make a semi-final. I need to be ready for a big fight."

David Ferrer ground Kei Nishikori into submission and although happy with his form, he continues to work on his game. He said: "Today I played very good, one of the best matches on my career in Australian Open. I'm very happy with my game.

"I am trying to improve every year my game. I am trying to improve my serve. I am trying to play more aggressive with my shots. I am more quiet (calm) with myself, no? This is very important for to improve my game."

Kei Nishikori has admitted facing Ferrer forced him to change his gameplan. He said: "I tried to go aggressive, but I think I did too much than what I usually do. So I was missing too many, too many unforced errors. And also he was playing good, you know. He didn't miss much, and he gets every ball. Yeah, it was tough for me to play."